Graphene is a carbon allotrope that is theoretically embodied in a singular plane of carbon atoms. Graphene is commonly represented in the literature as a two dimensional honeycomb lattice with sp2-bonded carbon atoms. In practice, those of ordinary skill in the art often refer to graphene as carbon material represented not only as a singular plane but also as multiple layers of singular carbon planes. Due to its unique structure, graphene possesses outstanding electrical mobility, or charge transport properties, but demonstrates little optical absorption. The noted features of graphene make it very desirable in certain applications, such as, semiconductor and photovoltaic articles.
Thermodynamically stable solutions of graphene have been created through conventional processes. In certain processes, common graphite is exfoliated and then dissolved into single-layer sheets of graphene. Graphene may be capable of imparting very desirable mechanical, thermal, chemical and electrical properties in its application. However, solution delivery of graphene becomes problematic due to the relatively large volume of solvent present with the graphene. The removal of the solution must be addressed in order to render the delivery of graphene viable using this format.
Electrically conductive materials may be employed as fillers in polymeric matrices. Conventional conductive fillers, such as carbon black, are added to polymer compositions at significantly larger loading levels of generally 15-25 percent by weight, leading to embrittlement and the loss of impact resistance. Carbon nanotubes are similarly effective at relatively lower loading levels than carbon black, specifically less than 5 percent by weight. However carbon nanotubes are expensive, offer poor structural reinforcement, and create industrial hygiene concerns through their handling and use. The conductive polymer field would benefit from advances that address conductivity without adversely affecting other properties of the polymer composite.